1. Field of the Invention
This invention relates to protective coatings for surfaces. In one of its aspects, the invention relates to a composition for protecting surfaces such as painted and unpainted metal, silverware, plastic surfaces, and the like. In another of its aspects, the invention relates to a composition for preserving fruits and vegetables.
2. State of the Prior Art
Polytetrafluoroethylene (Teflon) is a well-known synthetic plastic composition. For example, such polymers and methods for making the same are disclosed in United States Patents to Brubaker U.S. Pat. No. 2,393,967 and Berry U.S. Pat. No. 2,559,752. Such products in solid form have a great many uses such as in self-lubricating bearings, liner materials for handling corrosive materials, insulators for electrical conductors and many other uses. These materials also find use as adhesively applied liners for cooking ware and the like for ease of cleaning. Such liners, however, are relatively thick opaque coatings which require special processes of application.
An example of such a process and special composition is disclosed in U.S. Pat. No. 3,260,693, issued July 12, 1966, to Stand. The disclosed composition is a polytetrafluoroethylene dispersion in a liquid polar organic compound selected from the group consisting of trichloro-trifluoro-acetone, monochloro-defluoro-acetic acid and dichloro-tetrachloro-acetone, and a diluent of an organic liquid selected from the group consisting of trichloroethylene, methyl ethyl ketone, methyl isobutyl ketone, dimethyl formamide, tetrahydrofuran, carbon tetrachloride and hexachloroethane. The polytetrafluoroethylene particles have a preferable size in the range of 100-500 microns. This solution produces a relatively heavy opaque coating of the polytetrafluoroethylene. Further, the polar organic compounds form strong solvents which make the solution undesirable for painted surfaces.
The noncorrosive properties of Teflon make it suitable for many purposes. However, its relative insolubility makes it difficult to apply in thin even coatings so that the original color and appearance of the surfaces are retained. Thus, when used as a coating, the Teflon layer has heretofore completely covered the surface with a thickness such that the Teflon appears as a film on the surface. Insofar as I am aware, no systems have been developed for application of a transparent protective coating of Teflon by the consumer to surfaces which he desires to protect.